An axonal form of Charcot-Marie-Tooth disease showing distinctive featuresin association with mutations in the peripheral myelin protein zero gene (Thr124Met or Asp75Val)

Objectives and Methods-Seven families were studied with an axonal form of C harcot-Marie-Tooth disease (CMT) associated with mutations in the periphera l myelin protein zero (MPZ) gene-Thr124Met or Asp75Val. Results-Patients with these mutations commonly showed relatively late onset sensorimotor neuropathy predominantly involving the lower limbs. Sensory i mpairment typically was marked, and distal muscle atrophy and weakness were also present in the legs. Adie's pupil and deafness were often present, an d serum creatine kinase concentrations were often raised irrespective of wh ich MPZ mutation was present. Relatively well preserved motor and sensory n erve conduction velocities contrasted with reduced or absent compound muscl e action potentials and sensory nerve action potentials. Axonal change with marked axonal sprouting was seen in sural nerve specimens. Conclusion-The similar associated clinical findings suggest that patients w ith axonal CMT with an MPZ gene mutation share distinctive clinical feature s.